Ebola virus (EBOV; also known as Zaire ebolavirus) (family Filoviridae) is among the most lethal infectious agents known, producing sporadic outbreaks of severe, and highly lethal hemorrhagic fever in humans and nonhuman primates (NHPs). Owing to high morbidity and mortality rates in natural outbreaks, lack of prophylactic and treatment options, aerosol transmission potential, and their highly virulent nature, Ebola viruses have been identified as both NIAID Category A Priority pathogens and CDC Category A Agents of Bioterrorism. Despite this, the current standard of care is limited to palliative treatment and no therapeutic interventions have been approved against EBOV infection. Among many prophylactic and therapeutic platforms currently under development, monoclonal antibody (mAb) technology has emerged as one ofthe most promising treatment methods. Worldwide, there exist ~100 mAbs against EBOV that have been characterized to varying degrees. Six of these mAbs have demonstrated complete to partial protection of NHPs when administered from 1 to 4- 5 days after lethal infection. The goal of Project 1 is to achieve total protection in NHPs as late as possible in the course of infection with an